Magnet system



H. SPODIG MAGNET SYSTEM Filed July 9, 1954 PRIOR ART Oct. 27, 1959 EL76 59 E2710 Hi9]! United States Patent MAGNET SYSTEM Heinrich Spodig, Dortmund-Wambel, Germany Application July 9, 1954, Serial No. 442,401

3 Claims. (Cl. 317-2015) This invention relates to a device for attracting and collecting magnetizable particles from a fluid, for in- Stance, oil. It is a continuation-in-part of my co-pending application Serial No. 159,920, filed May 4, 1950, now abandoned.

Magnetic systems of the above denoted type are used for separating and filtering ferro-magnetic solid particles from granular materials from gaseous or vaporous media or from liquids, such as particularly machine oil or in brication oil. Such filters are provided, for example, in a suitable portion of the pressure conduit or of the return conduit of the oil such as a lubricating oil circulating through a metal working machine. The filter is usedto attract the dust, filings or metal particles which are produced by the working of the metal.

In view of the abrasive action of these metallic particles they frequently cause extensive damage to sliding surfaces or other movable machine parts to be lubricated.

It is customary to attach such filters to the walls of the gear housings of automobiles and machines, lubricating oil tubes, crank cases and the like to remove from the same abrasive particles.

The known magnetic filters are inefficient and rarely used in view of their inherent disadvantages although the need of these filters for the above recited purposes is generally recognized.

Thus it has been proposed to use a rod-shaped or horse shoe magnet which projects into the medium to be cleaned. The ferromagnetic particles are attracted to the poles of the magnet and these accumulations are easily removed by a medium flowing past the magnet pole. Thus the particles are swept again into the medium and since they are magnetized they cling together and cause still greater destruction in the machine.

For the same purpose it has been proposed to use magnet systems comprising permanent magnets and ferromagnetic soft iron pieces having an air gap across which a magnetic field is created. However, the action of a magnetic field created in such air gaps is comparatively Weak so that only few ferromagnetic particles are collected in the comparatively small space of the air gap.

Furthermore, stray magnetic fields are formed even outside of the air gap which will attract ferromagnetic particles that will assume bulge-like shapes. The stray magnetic fields which are farthest removed from the air gap will only weakly attract the particles. In this case, the ferromagnetic accumulations of filtered particles which project into the fiowing medium, such as a circulating lubricating oil, are swept again into the medium as a conglomeration of particles which then again exercise their detrimental action.

Besides these detrimental drawbacks most of the known magnet systems have uncontrollable magnetic stray fields originating from various places of their surfaces. These stray fields will also attract ferromagnetic particles which again get into the fluid circulating fluid so that they will cause further damage.

It is an object of the invention to provide an improved ice I magnet system for attracting and removing ferromagnetic particles from a fluid, such as oil which avoids the above denoted disadvantages of the art.

, A further object of the invention is to provide a permanent magnet system for the purposes specified which create a strong attractive force onto the ferromagnetic particles pulled from a fluid flow and which will substantially prevent that such particles are washed away again by the flow to be cleaned.

Another object of the invention is to provide a magnet system which has substantially no uncontrollable stray magnetic fields and which has a space suitable for collecting a large number of ferromagnetic particles.

The invention will now be described more in detail and with reference to the accompanying drawing.

In the drawing, i

Figures 1, 2, 3, 4 denote vertical cross sectional views of customary magnet systems of the above denoted type;

Figures 5, 6, 7, 8 denote vertical sectional views of magnet systems constructed in conformity with the invention;

Figures 9, 10, 11 are vertical cross sectional views of the latter illustrating their mode'of operation.

As apparent from Figures 1, 2, showing a customary separator of the instant type, a permanent magnet rod 1 is shown of which one pole, for instance, the-north pole is secured to the bottom of a soft iron shell 2, which is open at the top. Consequently, a ring-shaped or annular N pole is formed along the upper edge of the shell or pot '2 and a south pole S on the free end of magnet 1 which is disposed in the center of the shell. Between the two poles an air gap is formed through which a magnetic field of narrow width extends. If such a magnet system is used to attract ferromagnetic particles, the particles are collected in the formed magnetic field whereby the particles may accumulate in radially directed stray fields. These accumulated particles project, for example, into the circulating lubricating oil which may easily remove the particles whereupon they continue to circulate and cause extensive destruction of the sliding machine surfaces to be lubricated. Furthermore, such magnet systems have uncontrollable magnetic stray fields originating from the outer surface of the pot 2 which also attract ferromagnetic particles from the medium to be filtered.

If the permanent magnet 1 is lengthened in the usual manner beyond the edge of the shell or pot 2, as shown in Figs. 2, 3 and 4, the magnetic lines of force become more numerous corresponding to the increase of the magnetic volume of the two poles N and S. On the other hand, the uncontrollable stray fields are also increased and accordingly, the above described detrimental influences are increased which may lead to the destruction of the machine. These magnetic effects are generally known.

However, if the permanent magnet is shortened to only reach far below the upper edge of the shell and if therefore the magnet rod 1 extends only up to about half of the height of the shell wall, the above described disadvantages are entirely eliminated. The free pole 5, Figure 5, of the magnet still has a large number of magnetic lines but the annular N pole of the shell or pot 2 becomes non-magnetic. The uncontrollable stray fields at the outer surface of the magnet system have completely disappeared. This unexpected magnetic effect makes it possible to provide a closed useful magnetic field which is directed towards the interior of the system and which has a larger capacity than the known magnetic filters for collectiong ferromagnetic particles.

Preferably, such magnet systems in accordance with the invention are provided with a diamagnetic material 3 (Fig. 6), such as brass, copper, aluminum or with a nonmetallic material which may, for example, be cast between nagnet rod 1 and the interior of the pot 2. This diamagnetic material 3 preferably is fiush with the S pole of rod 1 to fill entirely the air gap which is formed between rod 1 and shell 2, Thus if the ferromagnetic particles to be attracted should collect in this spacethis would make the cleaning of the filter more diflicult and could cause a premature magnetic short circuit. The upper edge of the pot 2 may be flared (Fig. 7) thereby toin'crease the space for collecting the ferromagnetic particles to be attracted. Furthermore, the open top of the pot 2, Fig 8, may be closed and protected by a diar'n'agnetic, perforated cover plate which should permit the ferromagnetic particles to pass. I

The operation of a magnet system in accordance with the invention is illustrated in Figs. 9 to ll where the magnetic field and the attracted and oriented particles are indicated. The ferromagnetic particles to be separated from some medium are attracted (Fig. 9) by the inner magnetic field of the system and attach themselves at first to the origin of the magnetic lines of force of the magnet pole S. There they adhere very strongly and build upfurther until they orient themselves towards the side walls of the interior of the magnet pot to finally close the magnetic circuit (Fig. 10). The accumulation of the particles continues in this manner until the entire inner space is filled with ferromagnetic particles up to the edge of pot 2 (Fig. 12). The system is now completely magnetically short circuited. There are no magnetic stray fields which project into the flowing medium, and therefore, no ferromagnetic accumulations exist which cause the previously described damage to the machines. The gradually progressing filter process thus represents a strong magnetic suction effect which acts toward the interior of the system. The collected ferromagnetic particles are strongly attracted by their magnetic cohesion. 7

The invention has been described with reference to a preferred embodiment and it will be understood that many variations and modifications thereof may be resorted to without departure from the scope of the invention as defined in the following claims.

I claim: I

1. A device for attracting and collecting magnetizable particles from a fluid, said device comprising a hollow tublar shell of a magnetic material, said shell being closed at its bottom and open at its top, a rod-shaped rnagnet having its magnetic poles at its" two ends and being centrally located within said shell, the lower pole of said magnet contacting the inner bottom surface of said shell, the opposite upper pole being disposed below the upper edge of said shell, said magnet reaching up to about one half of the height of the shell, the space between said shell and said magnet being filled with a diamagnetic material extending substantially flush with said upper pole.

2. A device for attracting and collecting magnetizable particles from a fluid said device comprising a cylindrical shell of a magnetic material said shell being closed at its bottom and open at its top, a cylindrical rod-shaped magnet having its magnetic poles at its two ends and being centrally located within said shell, the lower pole of said magnet contacting the inner bottom surface of said shell, the opposite upper pole being disposed below the upper edge of said shell, said magnet reaching up to about half of the height of the shell, the space between said shell and said magnet being filled with a diamagnetic material extending substantially flush with said upper pole, said shell reaching with about half of its height beyond the upper pole of said magnet, and a perforated diamagneti'c cover extending across the open upper end of said shell to permit access to the free space within said shell through the perforations of said cover exclusively.

3. A device for attracting and collecting magneti'zable particles from a fluid said device comprising a cylindrical shell of a magnetic material said shell being closed at its bottom and open at its top, a cylindrical rod-shaped magnet having its magnetic poles at its two ends and being centrally located within said shell, the lower pole of said magnet contacting the inner bottom surface of said shell, the opposite upper pole being disposed below the upper edge of said shell, said magnet reaching up to about half of the height of the shell, the space between said shell and said magnet being filled with a diamagnetic material extending substantially flush with said upper pole, said shell reaching with about half of its height beyond the upper pole of said magnet, and extending outwardly with its upper half beyond the upper end of said magnet.

References Cited in the file of this patent UNITED STATES PATENTS 2,242,830 Lisle May 20, 1941 2,436,740 Brooks Feb. 24, 1948 2,450,630 Bourne Oct. 5, 1948 2,613,246 Spodig Oct. 7, 1952 FOREIGN PATENTS 62,534 Denmark Aug. 7, 1944 

